Electric-arc furnace



Nav. 17, 1925. "1561,731

F. KOSTKA ELECTRIC ARC FURNACE Filed Dec. 30,' 1924 Patented Nov.17,1925.

' UNITED STATES PariazNTl OFFICE.

:FRITZ KOSTKA; OF DUSSELDORF, GERMANY, ASSIGNOR T RHEINISCHE METALL-'WAABEN-UND MASCHINENFABRIK, OF DUSSELDORF-DERENDORF, GERMANY.

ELECTRIC-Anc rURNAcn Application led December 30, 1924. Serial No.758,863.

To all whom t may concern.' j

Be it known that I, FRITZ KosrKA, a citi- Yzen of Czechoslovakia,residing at Dusseldorf, Germany, Karlstrasse 98, 4have invent- 5 edcertain new and useful Improvements 1n or Relating to Electric-ArcFurnaces, of which the following is -a specification.

In electric arc furnaces the electrodes passing through the furnace Wallare surrounded by a tube of electrically non-conducting material whichis carried by a metal sleeve connected to the metal jacket of thefurnace. Even if the holes in the fire-proof furnace vWall for thereception of the packing for the electrodes are made with the utmostcare cracks are easily formed in said wall. During the smelting ofmetals which easily convert into vapor, or-alloys containing suchmetals, the vapors escape through thel cracks, and thereby condense atthe outer surface and cause short-circuits by bridging over Athemetallic-parts which necessarily must be insulated.

The purpose of this invention is to eliminate this drawback by providinga sleeve around the tube surrounding the electrode consisting also ofnon-conducting material in which one end is ein/bedded in the fireprooffurnace wall and the other end holds the metallic part of the packingfor the electrodes at a distance separated from the furnace jacket thatshort-circuiting is absolutely prevented.

The drawing shows one'mode of carrying out the invention and shows aside view partly in section.

'The tire-proof furnace wall B is surrounded by an insulating layer andat the outer surface by a metallic jacket. The end of the 0 electrodelying in the furnace wall is sur-4 rounded by a tube E of non-conductingmaterial which is carried by a metal sleeve D. The sleeve D is insulatedat G. from and screwed into the furnace wall A. At the exit point fromthe furnace the tube E is surrounded by a sleeve H which alsoconi sistsof a material which is a non-conductor of electricity. One end of saidsleeve is embedded in the reroof wall. or in the in- 5 sulating layer ofthe v rnaoe while the other` vend abuts against the metal sleeve D andholds it separated from the furnace mantle A in such a manner as toabsolutely prevent short circuits.

I claim:

1. In electric arc furnaces for melting metals the combination ofv anelectrode with a tube surrounding the part of the electrode lying in thefurnace wall and a sleeve of non-conducting material surrounding thetube, one end of the` sleeve being embedded in the fire-proof furnacewall While the othei1 end holds the metallic part of the acking for theelectrode at such a distance rom the wall of the furnace thatshort-circuiting is prevented.

2. A short circuit preventing device for the electrodes of electric arcfurnaces comprising an insulating sleeve having one end embedded in thefurnace wall and the other end extending beyond the outside wall of thefurnace; and a tube mounted in said sleeve adapted to have the electrodemounted therein and projected therethrough whereby short circuitsfrom-the electrode to the Walls of the furnace are prevented by means ofsaid sleeve. I

3. A short circuit preventing device for the electrodes of electric arcfurnaces comprising an insulating sleeve having one end embedded in thefurnace Wall and the other end extending beyond the outside Wall of thefurnace; a tube mounted in said sleeve; and a metal sleeve on said tubeabutting against said insulating sleeve and adapted to have theelectrode `mounted thereon and projected therethrough whereby short cir'cuits from the electrode to the walls of the vfurnace are prevented bymeans of said firstnamed sleeve.

4. A short circuit preventing device for the electrodes of electric arcfurnaces com prisin an insulating sleeve mounted in the wall o thefurnace and adapted to space thc metallic -part of the packing' for the'electrode a dlstance from the outside wall of the furnace. j. v

In testimony whereof I have aflixed my signature.

FRITZ KOSTKA.`

